Radio receiving apparatus



May 11, 1937. E. TOTH ET AL RADIO RECEIVING APPARATUS Filed NOV. 12, 1935 FREQUENCIES DISTRIBUTION FREQUENCIES DISTRIBUTION WITHOUT COMPENSATOR WITH COMPENSATDR RESONANT PERIOD OF ACOUSTIC I COMPENSATOR \Y I Fig. 6

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SPEAKER FREQUENCY RESPONSE WITHOUT ACOUSTIC COMPENSATOR Patented May 11, 1937 RADIO RECEIVING APPARATUS iEmerick'Toth,Flushing, N. Y-yfifld William H.

- Cooper; Passaic, N., J.

, assignors to, Pilot Radio Corporation, Long IslandGity, N. Y., a corporation of, New .York

"Application November 12,1935, Serial No. 49,334

4 Claims.

This invention'relates, toimprovements in'radio receiving apparatus, being-particularly directed to a visual resonancedevice and-mounting thereof in the receiver cabinet lnassociationwith the 5 speaker assembly.

Broadly, it "is-an object of this invention to provide for a-visual-resonance device adapted to be disposed for observationat the front of a radioreceiver cabinet, the visual resonance device being assembled and'mounted within thecone of a loud speaker assembly, whereby'to provide for prominent dispositionof the indicator device in the cabinetand at thesame time toprovide for compensation' with respect to the response of the loud speakerto various ranges of frequencies,

Up to the present timeyone of the difiiculties in radio receiver construction lies in the fact that visual resonance indicators, particularly the cath- -ode type'mechanism to indicate the attainment of optimum conditions'within-the receiver, has been disposed in various positions normally in unsymmetrical relationship with respect to the visible elements of a radio receiver; further, it has been found that a normal loud speaker of a radio receiver delivers in its response unwanted variations from the normal with respect to the higher frequency ranges.

With respect to these two deficiencies, it is the object of this invention to provide for a symmetrical and prominent disposition of the visual resonance device with respect to the cabinet and l at the same time to provide for a constructional assembly of such visual resonance device in relation to the cone of the loud speaker assembly as to cause a diversion from the normal path of sounds from the response of the loud speaker to the higher frequency ranges, as to produce through this compensation a desired effect, as, for example, a specific response curve having a straight line function.

Specifically, it is an object of this invention to provide for the disposition within the cone section of a loud speaker assembly of a visual 45 resonance indicator assembly of such construction as to provide for prominent symmetrical dispositioning of the visible resonance indicator at the face of the cabinet, while at the same time, due to its location within the cone of the loud speaker assembly, provide for directional displacement of the sound waves, developed in the speaker, particularly those in the high frequency ranges, whereby irregularities or peaks of the normal loud speaker curves as to the response for such high frequency ranges may be com pensated'for and reduced to provide a substantial I straight linecurve for response characteristics.

These and other advantages, capabilities and "features of theinvention will'appear fromsthe subjoined detailed description of one specific'ern- 5 bodiment thereof illustrated in thetaccompanying drawing, in which Figure 1 is :a': side elevation in .section;of the device.

Figure-.Zisaa front elevation. a

Figure 3 isiaggraphical representation of the field pattern normally produced through a loudspeaker .unit.

Figured: isa graphical representation of the field pattern in the loud speaker unit assembly, incorporating the'applicants device.

Figure 5 is I :agraph showing .the response at various frequencies for, a loudspeaker unit.

Figure 6 is a; graph showing theresponse at various frequencies fora loudspeaker unit incorporating the applicants, device.

,lReferring. to -=t he reference charactersin the drawing, numeral l0 represents the front panel of a radio receiver having a latticed grill I i, behind which is disposed a loud speaker assembly 5 S incorporating the armature unit 12, the vibrating cone l3, and the peripheral supporting cone ring I4 the speaker assembly being mounted adjacent the baille board l5 disposed to the rear of the panel about the periphery of the grill.

Within the hollow of the cone l3 and substantially centrally thereof, and concentric therewith, there is disposed a metallic conical casing 16, the same being firmly mounted by means of radially extending brackets ll, the ends I8 of which are 35 attached to the outer surface thereof, and the free ends H) of which are fastened between the cone ring l4 and the bafile board l5. Within the metallic conical casing Hi there is disposed a visual resonance tube 20, of the cathode ray type, the same being mounted in socket 2|, disposed within the restricted aperture of cone l6, from which socket extends cable 22 leading to an electrical source in the socket for actuating the visual resonance tube.

The head 23 of the visual tuning tube extends forwardly of the large aperture of the conical casing l6 and passes through aperture 24 formed centrally of the grill l l, the aperture 24 beingbounded by decorative bead 25, so as to present for ready observation the visual ray or beam developed in the electrode unit 26 disposed in said bead.

In this manner, the visual resonance medium is disposed for ready observation in a most central location with respect to the front panel of a radio 55 receiver, while at the same time eliminating the necessity of additional space or mounting of the same through the application of the area within the hollow of the cone of the loud speaker; in ,addition thereto, the metallic cone I6, in which the visual resonance tube is mounted, serves for an added function, to provide an acoustic compensator for the purpose of minimizing the distortion effect normally developed in the response ,of a loud speaker as relates to the sound beam ef- 'fect developed at high frequencies.

With reference to Figures 3 and 4, the frequency distribution or the field pattern in the normal loud speaker, shown in Figure 3, indicates ,the production of an unwanted, unsymmetrical ,high frequency beam, whereas with the application of the applicants device, as indicated in Figure 4, the high frequency beam is symmetrical with respect to the remaining lower frequency beams and is more evenly distributed.

As shown graphically in Figures 5 and 6, in the relative response-frequency curves, the normal curve of a loud speaker, asshown in Figure 5, indicates the presence of peaks, particularly at high frequencies, with the resultant distortion; to minimize this peak, the application of the conical casing, as indicated, provides a compensating effect with the result that the curve at the high frequencies is flattened to bring about a substantially straight line response-frequency curve.

It is obvious that various changes and modifications may be made to the details of construction without departing from the general spirit of the invention as set forth in the appended claims.

We claim:

1. In a device of the class described, in combination with a cabinet incorporating a loud speaker assembly mounted on the panel thereof, a visual resonance indicator disposed within the cone of the loud speaker assembly and projecting through the panel, and a supporting casing for said visual resonance indicator mounted on the panel and having a wall formation extending at an angle difierent from that of the cone of the loudspeaker to provide a change in the distribution for certain ranges of the high frequency response of the speaker.

2. In a device of the class described, in combination with a cabinet incorporating a loud speaker assembly mounted adjacent the front panel thereof, a visual resonance indicator disposed Within the cone of the loud speaker assembly, and visible at the front panel, and a supporting casing for said visual resonance indicator mounted within the cone of the loud speaker, to provide a change in the distribution for certain ranges of the high frequency response of the speaker.

3. In a device of the class described, in combination with a cabinet incorporating a loud speaker assembly disposed adjacent the grilled front panel thereof, a casing disposed within the cone of said loud speaker assembly, and a visual resonance indicator supported in said casing, said visual resonance indicator being disposed as to project in the grill of the front panel for observation and the supporting casing being so formed and positioned as to rearrange the field pattern with respect to the frequency distribution normally developed in the loud speaker.

4. In a device of the class described, in combination with a cabinet incorporating a loud speaker assembly mounted on the panel thereof, a visual resonance indicator disposed within the cone of the loud speaker assembly and projecting through the panel, and a supporting casing for said visual resonance indicator mounted within the cone of the loud speaker and having a wall formation extending at an angle different from that of the cone of the loud speaker, to provide a change in the distribution for certain ranges of the high frequency response of the speaker.

EMERICK TOTH.

WILLIAM H. COOPER. 

